The fuse box is under the hood - the rear defrost should have a fuse, if that does not help - contact your nearest Toyota service or parts department......Mike
The rear windscreen defroster does not work. I have pressed the right button to defrost the windscreen when raining or cold
If you are having rear defrost issues, I have a 93 also. There is a rear defrost relay that is constantly going bad. It is located under the driver side dash above the gas pedal. This shiny metal box was the cause of my failure. It may be yours to. There is also a fuse for the rear defrost in the fuse box. Check these and check the contacts out back at the rear window also.
The rear window defogger has a 25 amp fuse in the fuse panel behind the instrument cluster on the left side. Its fuse number 26 in the fuse panel.
Below the dash on the drivers side fuse box. Marked DEF
Click on the link below Click on Owner Guides The owners manual ( which includes the fuse diagrams ) can be viewed online Ford calls the rear defrost the heated backlight
Probably the rear defrost indicator.
There is no fuse, it is directly connected and when it burns out it destroys the wire harness. Found this out the hard way on my 07 Impala.
RIGHT NEXT TO THE BATTERY IN THE LITTLE BOX WITH FUSE ON TOP OF IT
The rear window defrost/defog heater grid.
I was looking at the 2004 Lincoln LS Owner Guide and it shows : In the rear Power Distribution Box ( with the spare tire ) ( # 29 is a 40 amp maxi fuse for the rear defroster )
I was looking at the ( 1996 ) Ford Windstar Owner Guide and it shows : In the Power Distribution Box ( which is " live " ) located in the engine compartment near the battery ( " M " is a 60 amp fuse for the Heated Backlight , that's what Ford calls their rear defrost )
According to the owner's manual, in the power distribution box in the engine compartment , there is a 30 amp cartridge fuse in location # 4 that is for the rear defrost. Also, on the top side of the fuse panel located under the dash on the driver's side, there is a relay for the rear defrost in location # 2. The manual states "see the dealer for service of relay box"